Always place the tiles in their desired position before attaching them, to make sure they will fit properly.
You will need to cut out bits of the tiles before you attach them to fit around the wall beams.
When setting the tiles, try to keep them snuggly together. This will help prevent moisture from getting between the tiles, and make the cage easier to clean.
Work your way across from one side to the other.
This is a view of the finished floor.
This is another view.